The principal objecfive of the Biostatistics Core will be to provide project investigators a centralized resource for statistical expertise. Statisfical issues will be addressed at all levels of investigation: from the design o experiments to the conclusions drawn from them, and from the maintenance of data quality to the modeling fo human studies and trials. In support of this objective, the specific aims ofthe Biostatistics Core include: 1. To collaborate with project investigators in the formulation of hypotheses and hypothesis testing strategies, and in the design of experiments. Phase I trials, and population studies. 2. To conduct the statistical analyses of data generated by project invesfigators including: descriptive summary statistics, data modeling, hypothesis tesfing, and methods of discovery. 3. To ensure that the following statistical principles are adhered to in all studies: modeling nuisance or block effects, controlling Type I error to produce reliable conclusions, using adequate sample sizes to control Type II error and avoid inconsistent conclusions, using randomization of conditions to avoid systematic errors, and decreasing measurement error to enhance precision. 4. To provide design expertise and oversight for the Phase I Trials and support the design of possible future Phase II trials. 5. To collaborate with the bioinformatics core for all microarray analyses. 6. To investigate or develop new statistical methodologies to direcfiy address difficult data or design problems. 7. To provide design and data analyfic support from senior biostafisficians for the new investigators responsible for the pilot projects. RELEVANCE (See instructions): The SPORE requires a variety of statistical support, from modeling population longitudinal data to hypothesis testing strategies for mulfiple measures in donor cell experiments. Expertise in experimental and trial design, statistical genetics, multiplicity problems, microarray analyses, and mixed modeling, and familiarity with CLL and AML were the requirements used for designing the pool of expertise found in this Biostafisfics Core.